A hybrid vehicle may be provided with a driveline disconnect clutch. The driveline disconnect clutch may be closed to couple an engine with an electric machine. The driveline disconnect clutch may be opened to decouple the engine from the electric machine. The engine may provide torque to the driveline when the driveline disconnect clutch is closed. The engine is stopped when the driveline disconnect clutch is open to conserve fuel. Nevertheless, it may be desirable to operate an engine in more than two modes where the engine is either off or providing torque to a driveline.
The inventors herein have recognized the above-mentioned disadvantages and have developed a driveline operating method, comprising: providing torque to a driveline coupled to vehicle wheels via an engine and a driveline integrated starter/generator (DISG); and entering a sailing mode during select conditions, the sailing mode including providing DISG torque to the driveline and idling the engine without providing engine torque to the driveline.
By conditionally operating an engine in a sailing mode where the engine idles without providing torque to a driveline, it may be possible to improve engine driveline torque response. Further, the engine may be operated at idle to allow fuel vapors to be purged from a fuel vapor canister and to permit other functions that benefit from operating the engine.
The present description may provide several advantages. Specifically, the approach may improve driveline torque response. Further, the approach may permit other functions that benefit from engine operation. For example, the engine may operate at idle to produce vacuum or to combust fuel vapors from a fuel canister.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.